Apparatus and method

ABSTRACT

[Object] To enable interference of directional beams between cells to further decrease. 
     [Solution] Provided is an apparatus including: an acquisition unit that acquires information about a directional beam that is provided from a neighbor base station of a base station, the directional beam serving as an interference source for a terminal apparatus connected to the neighbor base station among a plurality of directional beams which is able to be formed by the base station; and a control unit that decides an operation of the base station regarding transmission of a signal over the directional beam on the basis of the information.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/527,734, filed May 18, 2017, which is based on PCT filingPCT/JP2015/084945, filed Dec. 14, 2015, which claims priority to JP2015-015818, filed Jan. 29, 2015, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to apparatuses and methods.

BACKGROUND ART

In the Third Generation Partnership Project (3GPP), various techniquesfor improving the capacity of a cellular system are currently studied inorder to accommodate explosively increasing traffic. It is alsoenvisaged that the required capacity will become about 1000 times thecurrent capacity in the future. Techniques such as multi-usermulti-input multiple-input multiple-output (MU-MIMO), coordinatedmultipoint (CoMP), and the like could increase the capacity of acellular system by a factor of as low as less than ten. Therefore, thereis a demand for an innovative technique.

For example, as a technique for significantly increasing the capacity ofa cellular system, a base station may perform beamforming using adirectional antenna including a large number of antenna elements (e.g.,about 100 antenna elements). Such a technique is a kind of techniquecalled large-scale MIMO or massive MIMO. By such beamforming, thehalf-width of a beam is narrowed. In other words, a sharp beam isformed. Also, if the large number of antenna elements are arranged in aplane, a beam aimed in a desired three-dimensional direction can beformed.

For example, Patent Literatures 1 to 3 disclose techniques applied whena directional beam aimed in a three-dimensional direction is used.

CITATION LIST Patent Literature

Patent Literature 1: JP 2014-204305A

Patent Literature 2: JP 2014-53811A

Patent Literature 3: JP 2014-64294A

DISCLOSURE OF INVENTION Technical Problem

For example, when a base station performs beamforming, directional beamsformed by the base station may reach a neighbor cell. Particularly,directional beams of large-scale MIMO may reach a neighbor cell andcause high received power. Consequently, large interference may begenerated.

Accordingly, it is desirable to provide a system which enablesinterference of directional beams between cells to further decrease.

Solution to Problem

According to the present disclosure, there is provided an apparatusincluding: an acquisition unit that acquires information about adirectional beam that is provided from a neighbor base station of a basestation, the directional beam serving as an interference source for aterminal apparatus connected to the neighbor base station among aplurality of directional beams which is able to be formed by the basestation; and a control unit that decides an operation of the basestation regarding transmission of a signal over the directional beam onthe basis of the information.

In addition, according to the present disclosure, there is provided amethod including, by a processor: acquiring information about adirectional beam that is provided from a neighbor base station of a basestation, the directional beam serving as an interference source for aterminal apparatus connected to the neighbor base station among aplurality of directional beams which is able to be formed by the basestation; and deciding an operation of the base station regardingtransmission of a signal over the directional beam on the basis of theinformation.

In addition, according to the present disclosure, there is provided anapparatus including: a calculation unit that calculates an amount ofinterference from a reference signal for channel quality measurementtransmitted by a neighbor base station of a serving base station; adetection unit that detects a radio resource having a small amount ofinterference from among radio resources to which the reference signal istransmitted; and a reporting unit that reports the radio resource havinga small amount of interference to a base station.

Advantageous Effects of Invention

As described above, according to the present disclosure, it is possibleto further decrease interference of directional beams between cells.Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram for describing a weight set for large-scale MIMObeamforming.

FIG. 2 is a diagram for describing an example of a case in whichbeamforming of large-scale MIMO is performed.

FIG. 3 is a diagram for describing a relationship between multiplicationof weight coefficients and insertion of a reference signal.

FIG. 4 is a diagram for describing a relationship between multiplicationby a weight coefficient and insertion of a reference signal in a newapproach.

FIG. 5 is a diagram for describing an example of an environment in whichdirectional beams are not reflected.

FIG. 6 is a diagram for describing an example of an environment in whichdirectional beams are reflected.

FIG. 7 is a diagram for describing an example of interference betweendirectional beams of different cells.

FIG. 8 is a diagram for describing an example of a schematicconfiguration of a system according to an embodiment of the presentdisclosure.

FIG. 9 describes an example of a configuration of a base stationaccording to the present embodiment.

FIG. 10 is a block diagram illustrating an example of a configuration ofa terminal apparatus according to the present embodiment.

FIG. 11 is a sequence diagram illustrating a first example of aschematic flow of a process according to the present embodiment.

FIG. 12 is a sequence diagram illustrating a second example of aschematic flow of the process according to the present embodiment.

FIG. 13 is a sequence diagram illustrating a third example of aschematic flow of the process according to the present embodiment.

FIG. 14 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 15 is a block diagram illustrating a second example of theschematic configuration of the eNB.

FIG. 16 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 17 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the appended drawings, structural elements that havesubstantially the same function and structure are denoted with the samereference numerals, and repeated explanation of these structuralelements is omitted.

In addition, there are cases in the present specification and thediagrams in which constituent elements having substantially the samefunctional configuration are distinguished from each other by affixingdifferent letters to the same reference numbers. For example, aplurality of constituent elements having substantially the samefunctional configuration are distinguished, like terminal apparatuses200A, 200B, and 200C, if necessary. However, when there is no particularneed to distinguish a plurality of constituent elements havingsubstantially the same functional configuration from each other, onlythe same reference number is affixed thereto. For example, when there isno particular need to distinguish terminal apparatuses 200A, 200B, and200C, they are referred to simply as terminal apparatuses 200.

Description will be given in the following order.

1. Introduction

1.1. Related techniques1.2. Consideration related to present embodiment2. Schematic configuration of system3. Configuration of each apparatus3.1. Configuration of base station3.2. Configuration of terminal apparatus4. Technical features5. Processing flow6. Application examples6.1. Application examples related to base station6.2. Application examples related to terminal apparatus

7. Conclusion 1. INTRODUCTION

First of all, techniques related to an embodiment of the presentdisclosure and consideration related to the present embodiment will bedescribed with reference to FIGS. 1 to 7.

1.1. Related Techniques

Beamforming and measurement will be described as techniques related toan embodiment of the present disclosure with reference to FIGS. 1 to 4.

(1) Beamforming (a) Necessity of Large-Scale MIMO

In the 3GPP, various techniques for improving the capacity of a cellularsystem are currently studied in order to accommodate explosivelyincreasing traffic. It is envisaged that the required capacity willbecome about 1000 times the current capacity in the future. Techniquessuch as MU-MIMO, CoMP, and the like could increase the capacity of acellular system by a factor of as low as less than ten. Therefore, thereis a demand for an innovative technique.

Release 10 of the 3GPP specifies that eNode B is equipped with eightantennas. Therefore, the antennas can provide eight-layer MIMO in thecase of single-user multi-input multiple-input multiple-output(SU-MIMO). Eight-layer MIMO is a technique of spatially multiplexingeight separate streams. Alternatively, the antennas can providefour-user two-layer MU-MIMO.

User equipment (UE) has only a small space for accommodating an antenna,and limited processing capability, and therefore, it is difficult toincrease the number of antenna elements in the antenna of UE. However,recent advances in antenna mounting technology have allowed eNnode B toaccommodate a directional antenna including about 100 antenna elements.

For example, as a technique for significantly increasing the capacity ofa cellular system, a base station may perform beamforming using adirectional antenna including a large number of antenna elements (e.g.,about 100 antenna elements). Such a technique is a kind of techniquecalled large-scale MIMO or massive MIMO. By such beamforming, thehalf-width of a beam is narrowed. In other words, a sharp beam isformed. Also, if the large number of antenna elements are arranged in aplane, a beam aimed in a desired three-dimensional direction can beformed. For example, it has been proposed that, by forming a beam aimedat a higher position than that of a base station (e.g., a higher floorof a high-rise building), a signal is transmitted to a terminalapparatus located at that position.

In typical beamforming, the direction of a beam can be changed in thehorizontal direction. Therefore, it can be said that the typicalbeamforming is two-dimensional beamforming. Meanwhile, in large-scaleMIMO (or massive MIMO) beamforming, the direction of a beam can bechanged in the vertical direction as well as the horizontal direction.Therefore, it can be said that large-scale MIMO beamforming isthree-dimensional beamforming.

Note that the increase in the number of antennas allows for an increasein the number of MU-MIMO users. Such a technique is another form of thetechnique called large-scale MIMO or massive MIMO. Note that when thenumber of antennas in UE is two, the number of spatially separatedstreams is two for a single piece of UE, and therefore, it is morereasonable to increase the number of MU-MIMO users than to increase thenumber of streams for a single piece of UE.

(b) Weight Set

A set of weight for beamforming are represented by a complex number(i.e., a set of weight coefficients for a plurality of antennaelements). An example of a weight set particularly for large-scale MIMObeamforming will now be described with reference to FIG. 1.

FIG. 1 is a diagram for describing a weight set for large-scale MIMObeamforming. FIG. 1 shows antenna elements arranged in a grid pattern.FIG. 1 also shows two orthogonal axes x and y in a plane in which theantenna elements are arranged, and an axis z perpendicular to the plane.Here, the direction of a beam to be formed is, for example, representedby an angle phi (Greek letter) and an angle theta (Greek letter). Theangle phi (Greek letter) is an angle between an xy-plane component ofthe direction of a beam and the x-axis. Also, the angle theta (Greekletter) is an angle between the beam direction and the z-axis. In thiscase, for example, the weight coefficient V_(m, n) of an antenna elementwhich is m-th in the x-axis direction and n-th in the y-axis directionis represented as follows.

$\begin{matrix}{{V_{m,n}\left( {\theta,\phi,f} \right)} = {\exp\left( {j\; 2\; \pi \; \frac{f}{c}\left\{ {{\left( {m - 1} \right)d_{x}{\sin (\theta)}{\cos (\phi)}} + {\left( {n - 1} \right)d_{y}{\sin (\theta)}\sin \; (\phi)}} \right\}} \right)}} & \left\lbrack {{Math}.\mspace{14mu} 1} \right\rbrack\end{matrix}$

In formula (1), f is a frequency, and c is the speed of light. Also, jis the imaginary unit of a complex number. Also, d_(x) is an intervalbetween each antenna element in the x-axis direction, and d_(y) is aninterval between each antenna element in the y-axis direction. Note thatthe coordinates of an antenna element are represented as follows.

x=(m−1)d _(x) , y=(n−1)d _(y)  [Math. 2]

A weight set for typical beamforming (two-dimensional beamforming) maybe divided into a weight set for acquiring directivity in the horizontaldirection and a weight set for phase adjustment of dual layer MIMO(i.e., a weight set for phase adjustment between two antenna subarrayscorresponding to different polarized waves). On the other hand, a weightset for beamforming of large-scale MIMO (three-dimensional beamforming)may be divided into a first weight set for acquiring directivity in thehorizontal direction, a second weight set for acquiring directivity inthe vertical direction, and a third weight set for phase adjustment ofdual layer MIMO.

(c) Change in Environment Due to Large-Scale MIMO Beamforming

When large-scale MIMO beamforming is performed, the gain reaches 10 dBor more. In a cellular system employing the above beamforming, asignificant change in radio wave environment may occur compared to aconventional cellular system.

(d) Case where Large-Scale MIMO Beamforming is Performed

For example, a base station in urban areas may form a beam aimed at ahigh-rise building. Also, even in rural areas, a base station of a smallcell may form a beam aimed at an area around the base station. Note thatit is highly likely that a base station of a macro-cell in rural areasdoes not perform large-scale MIMO beamforming.

FIG. 2 is a diagram for describing an example of a case in whichbeamforming of large-scale MIMO is performed. Referring to FIG. 2, abase station 71 and a high-rise building 73 are illustrated. Forexample, the base station 71 forms a directional beam 79 toward thehigh-rise building 73 in addition to directional beams 75 and 77 towardthe ground.

(2) Measurement

Measurement includes measurement for selecting a cell and measurementfor feeding back a channel quality indicator (CQI) and the like afterconnection. The latter is required to be performed in a shorter time.Measurement of an amount of interference from a neighbor cell as well asmeasurement of quality of a serving cell may be considered as a kind ofsuch CQI measurement.

(a) CQI Measurement

Although a cell-specific reference signal (CRS) may be used for CQImeasurement, a channel state information reference signal (CSI-RS) hasmainly been used for CQI measurement since release 10.

A CSI-RS is transmitted without beamforming, similar to a CRS. That is,the CSI-RS is transmitted without being multiplied by a weight set forbeamforming, similar to a CRS. A specific example of this will bedescribed with reference to FIG. 3.

FIG. 3 is a diagram for describing the relationship betweenmultiplication of weight coefficients and insertion (or mapping) of areference signal. Referring to FIG. 3, a transmission signal 82corresponding to each antenna element 81 is complex-multiplied by aweight coefficient 83 by a multiplier 84. Thereafter, the transmissionsignal 82 complex-multiplied by the weight coefficient 83 is transmittedfrom the antenna element 81. Also, a DR-MS 85 is inserted before themultiplier 84, and is complex-multiplied by the weight coefficient 83 bythe multiplier 84. Thereafter, the DR-MS 85 complex-multiplied by theweight coefficient 83 is transmitted from the antenna element 81.Meanwhile, a CRS 86 (and a CSI-RS) is inserted after the multiplier 84.Thereafter, the CRS 86 (and the CSI-RS) is transmitted from the antennaelement 81 without being multiplied by the weight coefficient 83.

Since a CSI-RS is transmitted without beamforming as described above, apure channel (or a channel response H) which is not affected bybeamforming is estimated when measurement of the CSI-RS is performed.This channel H is used and a rank indicator (RI), a precoding matrixindicator (PMI) and a channel quality indicator (CQI) are fed back. Notethat only a CQI is fed back depending on a transmission mode. Also, anamount of interference may be fed back.

(b) CSI-RS

Since a CSI-RS is transmitted without beamforming before release 12 asdescribed above, the pure channel H which is not affected by beamformingis estimated when measurement of the CSI-RS is performed. Accordingly,the CSI-RS has been operated like a CRS.

A CRS is used for cell selection, synchronization and the like and thusa CRS transmission frequency is higher than a CSI-RS transmissionfrequency. That is, a CSI-RS period is longer than a CRS period.

There may be a first approach for transmitting a CSI-RS withoutbeamforming and a second approach for transmitting a CSI-RS withbeamforming (i.e., transmitting a CSI-RS over a directional beam) in alarge-scale MIMO environment. It can be said that the first approach isa conventional approach and the second approach is a new approach. Arelationship between multiplication by a weight coefficient andinsertion of a reference signal in the new approach (second approach)will be described below with reference to FIG. 4.

FIG. 4 is a diagram for describing relationship between multiplicationby a weight coefficient and insertion (or mapping) of a reference signalin the new approach. Referring to FIG. 4, a transmission signal 92corresponding to each antenna element 91 is complex-multiplied by aweight coefficient 93 by a multiplier 94. Thereafter, the transmissionsignal 92 complex-multiplied by the weight coefficient 93 is transmittedfrom the antenna element 91. Also, a DR-MS 95 is inserted before themultiplier 94, and is complex-multiplied by the weight coefficient 93 bythe multiplier 94. Thereafter, the DR-MS 95 complex-multiplied by theweight coefficient 93 is transmitted from the antenna element 91.Further, a CSI-RS 96 is inserted in front of the multiplier 94, and iscomplex-multiplied by the weight coefficient 93 in the multiplier 94.Then, the CSI-RS 96 complex-multiplied by the weight coefficient 93 istransmitted from the antenna element 91. Meanwhile, a CRS 97 (and anormal CSI-RS) is inserted after the multiplier 94. Thereafter, the CRS97 (and the normal CSI-RS) is transmitted from the antenna element 91without being multiplied by the weight coefficient 93.

1.2. Consideration Related to Embodiment of Present Disclosure

Consideration related to an embodiment of the present disclosure will bedescribed with reference to FIGS. 5 to 7.

(1) Interference Between Directional Beams (a) Intra-Cell Interference

In an environment in which directional beams formed by an eNB are notreflected, interference is not generated between directional beamsformed by the eNB. On the other hand, in an environment in whichdirectional beams formed by an eNB are reflected, interference may begenerated between directional beams formed by the eNB. A specificexample of this will be described below with reference to FIGS. 5 and 6.

FIG. 5 is a diagram for describing an example of an environment in whichdirectional beams are not reflected. Referring to FIG. 5, an eNB 11 andUEs 21, 23 and 25 are illustrated. For example, the eNB 11 forms adirectional beam 31 directed toward the UE 21, a directional beam 33directed toward the UE 23 and a directional beam 35 directed toward theUE 25. In this example, the directional beams 31, 33 and 35 are notreflected and interference is not generated among the directional beams31, 33 and 35.

FIG. 6 is a diagram for describing an example of an environment in whichdirectional beams are reflected. Referring to FIG. 6, an eNB 11 and UEs21, 23 and 25 are shown. Further, obstacles 41 and 43 are shown. Forexample, the obstacles 41 and 43 are buildings. For example, the eNB 11forms a directional beam 31 directed toward the UE 21, a directionalbeam 33 directed toward the UE 23 and directional beams 35 directedtoward the UE 25. In this example, the directional beams 35 arereflected by the obstacles 41 and 43 and arrive at the UE 23.Accordingly, interference is generated between the directional beam 33and the directional beams 35.

(b) Inter-Cell Interference

Not only interference between directional beams in a cell but alsointerference between directional beams of different cells may begenerated. A specific example of this will be described below withreference to FIG. 7.

FIG. 7 is a diagram for describing an example of interference betweendirectional beams of different cells. Referring to FIG. 7, eNBs 11 and13 and UEs 21, 23 and 25 are shown. For example, the eNB 11 forms adirectional beam 31 toward the UE 21, a directional beam 33 toward theUE 23 and a directional beam 35 toward the UE 25. In addition, the eNB13 forms a directional beam 37 which arrives at the UE 25. Accordingly,interference is generated between the directional beam 35 formed by theeNB 11 and the directional beam 37 formed by the eNB 13.

(c) Deterioration of Received Quality

As described above, when interference of a directional beam in a celland/or interference of a directional beam between cells are generated,received quality of a UE deteriorates, and thus system throughput maydecrease.

Interference may be generated between two directional beams orinterference may be generated among three or more directional beams. Howmany directional beams generate interference varies according to UEs.Referring to FIG. 6, for example, interference is not generated in theUEs 21 and 25, whereas interference is generated among three directionalbeams in the UE 23. That is, an interference situation varies dependingon place.

It can be said that a single operating band includes a high frequencyband (component carriers) and a low frequency band (component carriers)but interference situations in the frequency bands are nearly the same.

(2) Required Countermeasures

When only a desired directional beam arrives at a UE, the UE can obtainhigh received quality. On the other hand, when not only a desireddirectional beam but also other directional beams arrive at a UE,received quality of the UE may deteriorate.

In order to suppress such interference, first of all, it is importantfor an eNB to ascertain a situation of interference of a directionalbeam. A UE reporting a situation of interference of a directional beamto the eNB is considered because the eNB cannot be aware of thesituation of such interference of the directional beam. For example,calculating an amount of interference of a directional beam other than adesired directional beam from a CSI-RS is considered. Also, use of a CSIfeedback procedure is considered.

In general, there are two types of channel quality measurement. One typeis radio resource management (RRM) measurement such as measurement ofreference signal received power (RSRP) and reference signal receivedquality (RSRQ) and the other is measurement for deciding an RI, a CQI, aPMI and the like included in CSI. The former is mainly performed forcell selection by both a UE in an RRC idle mode and a UE in an RRCconnected mode. On the other hand, the latter is performed to recognizean interference situation by a UE in an RRC connected mode.

(3) CSI-RS

A CSI-RS is defined in release 10. A normal CSI-RS is also referred toas a non-zero-power CSI-RS. The purpose of the CSI-RS is to acquire apure channel and thus the CSI-RS is transmitted without beamforming.

Also, a zero-power CSI-RS is defined. The zero-power CSI-RS is definedin order to enable easy observation of relatively weak signals fromother eNBs. Since an eNB does not transmit a signal in radio resources(resource elements) for the zero-power CSI-RS, a UE can receive signalsfrom other eNBs in the radio resources.

A CSI-RS period is variable between 5 ms and 80 ms. In addition, 400radio resources are prepared in one subframe as candidates for radioresources in which the CSI-RS is transmitted.

Conventionally, only one CSI-RS is configured for one cell. On the otherhand, a plurality of zero-power CSI-RSs can be configured for one cell.Accordingly, when a serving eNB of a UE configures a zero-power CSI-RSin accordance with a configuration of a CSI-RS of a neighbor eNB, the UEcan perform measurement of the CSI-RS of the neighbor eNB without beingaffected by a signal from the serving eNB.

Note that a CSI-RS configuration is cell-specific. A UE may be notifiedof the configuration through signaling of a higher layer.

2. SCHEMATIC CONFIGURATION OF SYSTEM

Next, a schematic configuration of a communication system 1 according toan embodiment of the present disclosure will be described with referenceto FIG. 8. FIG. 8 is a diagram for describing an example of theschematic configuration of the communication system 1 according to anembodiment of the present disclosure. Referring to FIG. 8, the system 1includes a base station 100, a terminal apparatus 200, and a basestation 300. The system 1 is a system which complies with, for example,LTE, LTE-Advanced, or similar communication standards.

(Base Station 100)

The base station 100 performs wireless communication with the terminalapparatuses 200. For example, the base station 100 performs wirelesscommunication with the terminal apparatuses 200 located in a cell 101 ofthe base station 100.

Particularly, in an embodiment of the present disclosure, the basestation 100 performs beamforming. For example, the beamforming isbeamforming of large-scale MIMO. The beamforming may also be referred toas beamforming of massive MIMO, beamforming of free dimension MIMO orthree-dimensional beamforming. Specifically, for example, the basestation 100 includes a directional antenna usable for large-scale MIMOand performs beamforming of large-scale MIMO by multiplying atransmission signal by a weight set for the directional antenna.

For example, the base station 100 transmits a reference signal forchannel quality measurement over a directional beam. For example, thereference signal is a CSI-RS. Note that the embodiment of the presentdisclosure is not limited to such an example and the base station 100may transmit the reference signal without beamforming.

(Terminal Apparatus 200)

The terminal apparatus 200 performs wireless communication with a basestation. For example, the terminal apparatus 200 performs wirelesscommunication with the base station 100 when located within a cell 101of the base station 100. For example, the base station 200 performswireless communication with a base station 300 when located within acell 301 of the base station 300.

For example, terminal apparatuses 200A, 200B, 200C and 200D areconnected to the base station 100. That is, the base station 100 is aserving base station of the terminal apparatuses 200A, 200B, 200C and200D and the cell 101 is a serving cell of the terminal apparatuses200A, 200B, 200C and 200D.

For example, terminal apparatuses 200E, 200F, 200G and 200H areconnected to the base station 300. That is, the base station 300 is aserving base station of the terminal apparatuses 200E, 200F, 200G and200H and the cell 301 is a serving cell of the terminal apparatuses200E, 200F, 200G and 200H.

(Base Station 300)

The base station 300 is a neighbor base station of the base station 100.It may also be said that the base station 100 is a neighbor base stationof the base station 300.

For example, the base station 300 has the same configuration as the basestation 100 and performs the same operation as the base station 100. Inother words, the base station 100 has the same configuration as the basestation 300 and performs the same operation as the base station 300.

Although FIG. 8 illustrates only the base station 300 as a neighbor basestation of the base station 100, of course, the system 1 may include aplurality of neighbor base stations of the base station 100.

Note that both the base station 100 and the base station 300 may be basestations of macro cells. Alternatively, both the base station 100 andthe base station 300 may be base stations of small cells. Alternatively,one of the base station 100 and the base station 300 may be a basestation of a macro cell and the other of the base station 10 and thebase station 300 may be a base station of a small cell.

3. CONFIGURATION OF EACH APPARATUS

Next, examples of configurations of the base station 100 and theterminal apparatus 200 will be described with reference to FIGS. 9 and10.

3.1. Configuration of Base Station

First of all, an example of the configuration of the base station 100according to an embodiment of the present disclosure will be describedwith reference to FIG. 9. FIG. 9 is a block diagram showing an exampleof the configuration of the base station 100 according to the embodimentof the present disclosure. Referring to FIG. 9, the base station 100includes an antenna unit 110, a wireless communication unit 120, anetwork communication unit 130, a storage unit 140, and a processingunit 150.

(Antenna Unit 110)

The antenna unit 110 radiates a signal output by the wirelesscommunication unit 120, in the form of radio waves, into space. Theantenna unit 110 also converts radio waves in space into a signal, andoutputs the signal to the wireless communication unit 120.

For example, the antenna unit 110 includes a directional antenna. Forexample, the directional antenna is a directional antenna which can beused in large-scale MIMO.

(Wireless Communication Unit 120)

The wireless communication unit 120 transmits and receives signals. Forexample, the wireless communication unit 120 transmits a downlink signalto the terminal apparatus 200 and receives an uplink signal from theterminal apparatus 200.

(Network Communication Unit 130)

The network communication unit 130 transmits and receives information.For example, the network communication unit 130 transmits information toother nodes and receives information from other nodes. For example, theother nodes include other base stations (for example, base station 300)and a core network node.

(Storage Unit 140)

The storage unit 140 stores programs and data for operation of the basestation 100.

(Processing Unit 150)

The processing unit 150 provides various functions of the base station100. The processing unit 150 includes an information acquisition unit151 and a control unit 153. Note that the processing unit 150 mayfurther include other components in addition to such components. Thatis, the processing unit 150 may perform operations other than operationsof such components.

Specific operations of the information acquisition unit 151 and thecontrol unit 153 will be described below in detail.

3.2. Configuration of Terminal Apparatus

Next, an example of the configuration of the terminal apparatus 200according to an embodiment of the present disclosure will be describedwith reference to FIG. 10. FIG. 10 is a block diagram for showing anexample of the configuration of the terminal apparatus 200 according tothe embodiment of the present disclosure. Referring to FIG. 10, theterminal apparatus 200 includes an antenna unit 210, a wirelesscommunication unit 220, a storage unit 230 and a processing unit 240.

(Antenna Unit 210)

The antenna unit 210 radiates a signal output by the wirelesscommunication unit 220, in the form of radio waves, into space. Theantenna unit 210 also converts radio waves in space into a signal, andoutputs the signal to the wireless communication unit 220.

(Wireless Communication Unit 220)

The wireless communication unit 220 transmits and receives signals. Forexample, the wireless communication unit 220 receives a downlink signalfrom the base station and transmits an uplink signal to the basestation.

(Storage Unit 230)

The storage unit 230 stores a program and data for operation of theterminal apparatus 200.

(Processing Unit 240)

The processing unit 240 provides various functions of the terminalapparatus 200. The processing unit 240 includes an interference amountcalculation unit 241, a detection unit 243 and a reporting unit 245.Note that the processing unit 240 may further include components otherthan such components. That is, the processing unit 240 may also performoperations other than operations of such components.

Specific operations of the interference amount calculation unit 241, thedetection unit 243 and the reporting unit 245 will be described below indetail.

4. TECHNICAL FEATURES

Next, technical features according to the embodiment of the presentdisclosure will be described.

(1) Calculation of Amount of Interference of Directional Beam

For example, the terminal apparatus 200 (interference amount calculationunit 241) connected to the base station 300 calculates an amount ofinterference of a directional beam from a reference signal for channelquality measurement (e.g., a CSI-RS) transmitted by the base station100.

As an example, the base station 100 transmits a reference signal forchannel quality measurement over each of a plurality of directionalbeams which can be formed by the base station 100. In this case, theterminal apparatus 200 calculates an amount of interference of each ofthe plurality of directional beams from the reference signal for channelquality measurement transmitted over each of the plurality ofdirectional beams. Note that, for example, a configuration (e.g., aradio resource used for transmission and/or a signal of) of a referencesignal for channel quality measurement is different for each directionalbeam. Accordingly, it is possible to calculate an amount of interferenceof each directional beam.

As another example, the base station 100 may transmit a reference signalfor channel quality measurement without beamforming. In this case, theterminal apparatus 200 may estimate a channel from the reference signaland virtually calculate an amount of interference of each of theplurality of directional beams on the basis of the channel and aplurality of precoding matrices corresponding to the plurality ofdirectional beams. Specifically, the terminal apparatus 200 maycalculate an amount of interference I(i) of a directional beam i=H*PM(i)on the basis of a channel H and a precoding matrix PM(i) of thedirectional beam i.

Note that, instead of the terminal apparatus 200, the base station 300may virtually calculate an amount of interference of each of theplurality of directional beams on the basis of a channel reported by theterminal apparatus 200 (reporting unit 245) and the plurality ofprecoding matrices.

(2) Provision of Interference Beam Information

In the embodiment of the present disclosure, the base station 300 (i.e.,a neighbor base station of the base station 100) provides, to the basestation 100, information about a directional beam which is aninterference source for the terminal apparatus 200 connected to the basestation 300 (referred to as “interference beam information” hereinafter)from among a plurality of directional beams which can be formed by thebase station 100.

(a) Directional Beam which is Interference Source (a-1) Directional BeamHaving Large Amount of Interference

For example, the directional beam which is an interference source forthe terminal apparatus 200 is a directional beam having a large amountof interference (e.g., a directional beam having an amount ofinterference exceeding a threshold value) in the terminal apparatus 200.In this case, when there is a directional beam having a large amount ofinterference (e.g., a directional beam having an amount of interferenceexceeding a threshold value) in the terminal apparatus 200 connected tothe base station 300, the base station 300 provides information aboutthe directional beam (i.e., interference beam information) to the basestation 100.

More specifically, on the basis of an amount of interference of adirectional beam reported by the terminal apparatus 200 (reporting unit245), for example, the base station 300 determines whether the amount ofinterference of the directional beam is large (e.g., whether the amountof interference exceeds a threshold value). Thereafter, the base station300 provides information about the directional beam (i.e., interferencebeam information) to the base station 100 when it is determined that theamount of interference of the directional beam is large (e.g., theamount of interference exceeds the threshold value).

Alternatively, the terminal apparatus 200 may determine whether theamount of interference of the directional beam is large (e.g., whetherthe amount of interference exceeds the threshold value). Thereafter, theterminal apparatus 200 (reporting unit 245) may report the directionalbeam to the base station 300 when it is determined that the amount ofinterference of the directional beam is large (e.g., the amount ofinterference exceeds the threshold value). Then, the base station 300may provide the information about the directional beam (i.e.,interference beam information) to the base station 100.

(a-2) Directional Beam from which Amount of Interference is Calculated

The directional beam which is an interference source for the terminalapparatus 200 may be a directional beam from which an amount ofinterference in the terminal apparatus 200 is calculated. In this case,the base station 300 may provide information about the directional beamfrom which the amount of interference in the terminal apparatus 200 iscalculated (i.e., interference beam information) to the base station 100irrespective of whether the amount of interference is large or small. Inthis case, the base station 100 may determine whether the amount ofinterference of the directional beam is large (e.g., whether the amountof interference exceeds the threshold value).

(a-3) Others

The directional beam which is an interference source for the terminalapparatus 200 may be a directional beam which obstructs detection ofanother reference signal for channel quality measurement in the terminalapparatus 200. The other reference signal may be a reference signaltransmitted by another base station in the same radio resource as thatfor the reference signal transmitted by the base station 100. In thiscase, when there is a directional beam which obstructs the otherreference signal for channel quality measurement, the base station 300may provide information about the directional beam (i.e., interferencebeam information) to the base station 100.

(b) Interference Beam Information (b-1) Specification Information

For example, the interference beam information includes information forspecifying the directional beam (referred to as “specificationinformation” hereinafter).

As an example, the specification information is information whichindicates a precoding matrix (e.g., a PMI) used to form the directionalbeam.

As another example, a reference signal for channel quality measurement(e.g., a CSI-RS) may be transmitted over a directional beam and aconfiguration of a reference signal for channel quality measurement maybe provided to each directional beam. That is, a directional beam and aconfiguration may be correlated. In this case, the specificationinformation may be information indicating a configuration of a referencesignal for channel quality measurement.

Accordingly, the base station 300 may recognize a directional beam tohandle, for example.

(b-2) Interference Amount Information

The interference beam information may include information indicating theamount of interference of the directional beam. The amount ofinterference may be the amount of interference of the directional beamin the terminal apparatus 200 connected to the base station 300.Accordingly, the base station 300 may execute an operation depending onthe amount of interference, for example.

(c) Provision Technique

For example, the base station 300 generates a message (a message for thebase station 100) including the interference beam information.Thereafter, the base station 300 transmits the message to the basestation 100.

(3) Decision of Operation Related to Transmission Over Directional Beam

In the embodiment of the present disclosure, the base station 100(information acquisition unit 151) acquires the interference beaminformation (i.e., information about a directional beam which is aninterference source for the terminal apparatus 200 connected to the basestation 300 from among a plurality of directional beams which can beformed by the base station 100) provided by the base station 300.Thereafter, the base station 100 (control unit 153) decides an operationof the base station 100 regarding transmission of a signal over thedirectional beam on the basis of the interference beam information.

(a) Signal

For example, the signal includes a data signal.

For example, the signal includes a reference signal for channel qualitymeasurement. More specifically, the reference signal is a channel stateinformation reference signal (CSI-RS), for example.

(b) Operation (b-1) First Example (Suspension)

As a first example, the base station 100 (control unit 153) decidessuspension of transmission of the signal over the directional beam asthe operation. Thereafter, the base station 100 suspends transmission ofthe signal over the directional beam.

For example, the base station 100 (control unit 153) decides andexecutes suspension of transmission of a data signal and/or thereference signal over the directional beam.

Accordingly, it is possible to cancel interference of the directionalbeam in the terminal apparatus 200 connected to the base station 300,for example.

(b-2) Second Example (Restriction)

As a second example, the base station 100 (control unit 153) decidesrestriction on transmission of the signal over the directional beam asthe operation. Thereafter, the base station 100 restricts transmissionof the signal over the directional beam.

Data Signal

For example, the restriction includes restricting radio resources inwhich a data signal is transmitted over the directional beam. That is,the base station 100 (control unit 153) decides restriction on radioresources in which a data signal is transmitted over the directionalbeam and restricts the radio resources. Consequently, the base station100 transmits the data signal in the restricted radio resources over thedirectional beam.

More specifically, the restriction includes restricting, for example,time resources in which a data signal is transmitted over thedirectional beam. For example, the time resources are subframes. In thiscase, the base station 100 transmits the data signal in the restrictedsubframes over the directional beam.

Note that the restriction may include restricting frequency resources inwhich a data signal is transmitted over the directional beam. Also, therestriction may include restricting time and frequency resources inwhich a data signal is transmitted over the directional beam.

Reference Signal

For example, the restriction includes lengthening a period oftransmission of a reference signal for channel quality measurement. Thatis, the base station 100 (control unit 153) decides lengthening of aperiod of transmission of a reference signal for channel qualitymeasurement over the directional beam and lengthens the period. That is,the base station 100 (control unit 153) changes the period in theconfiguration of the reference signal for channel quality measurementtransmitted over the direction beam to a long period.

Accordingly, it is possible to suppress interference of the directionalbeam in the terminal apparatus 200 connected to the base station 300,for example.

(b-3) Third Example (Continuation)

For example, the base station 100 (control unit 153) decidescontinuation of transmission of the signal over the directional beam asthe operation. Thereafter, the base station 100 continuously transmitsthe signal over the directional beam.

Accordingly, it is possible to continue transmission of the signal overthe directional beam when it is difficult to suspend and restricttransmission of the signal over the directional beam, for example.

(b-4) Others

The restriction may include changing the configuration (e.g., radioresources used to transmit a signal (including a period) and/or asequence of the signal) of a reference signal for channel qualitymeasurement through the directional beam. That is, the base station 100(control unit 153) may decide changing of the configuration and changethe configuration.

As described above, the directional beam may be a directional beam whichobstructs detection of another reference signal for channel qualitymeasurement (e.g., another CSI-RS) in the terminal apparatus 200. Thebase station 100 (control unit 153) may decide changing of theconfiguration and change the configuration.

Accordingly, the terminal apparatus 200 connected to the base station300 can detect another reference signal for channel quality measurement,for example.

(c) Operation Decision Technique

For example, the base station 100 (control unit 153) decides anoperation of the base station 100 from among the aforementioned variousoperations. Hereinafter, examples of a technique for deciding theoperation will be described. Note that decision of the operationaccording to the present embodiment is not limited to such examples.

Decision Based on Situation of Transmission of Data Signal

For example, the base station 100 may transmit a data signal to neitherof terminal apparatuses 200 over the directional beam. In this case, thebase station 100 (control unit 153) decides and executes suspension oftransmission of the data signal over the directional beam, for example.

For example, the base station 100 transmits a data signal to a smallnumber of terminal apparatuses 200 (e.g., a number of terminalapparatuses 200 equal to or less than a predetermined number) over thedirectional beam. In this case, for example, the base station 100(control unit 153) decides and executes restriction on transmission ofthe data signal over the directional beam (e.g., restriction on radioresources in which the data signal is transmitted over the directionalbeam).

For example, the base station 100 transmits a data signal to a largenumber of terminal apparatuses 200 (e.g., a number of terminalapparatuses 200 exceeding a predetermined number) over the directionalbeam. In this case, for example, the base station 100 (control unit 153)decides and executes continuation of transmission of the data signalover the directional beam.

Decision Based on Situation of Disposition of Terminal Apparatus 200

For example, the number of terminal apparatuses 200 connected to thebase station 100 and located in a radiation direction of the directionalbeam is small. More specifically, the number of terminal apparatuses 200located in the radiation direction of the directional beam is equal toor less than a predetermined number, for example. In this case, the basestation 100 (control unit 153) decides and executes suspension of orrestriction on transmission of a data signal and/or a reference signalfor channel quality measurement over the directional beam.

For example, the number of terminal apparatuses 200 connected to thebase station 100 and located in the radiation direction of thedirectional beam is large. More specifically, the number of terminalapparatuses 200 located in the radiation direction of the directionalbeam exceeds the predetermined number, for example. In this case, thebase station 100 (control unit 153) decides and executes continuation oftransmission of a data signal and/or a reference signal for channelquality measurement over the directional beam.

Note that the predetermined number may be equal to or larger than 1 ormay be 0.

As described above, the base station 100 (control unit 153) decides anoperation of the base station 100 regarding transmission of the signalover the directional beam on the basis of the interference beaminformation. Accordingly, it is possible to further decreaseinterference of a directional beam between cells (i.e., between the cell101 and the cell 301), for example.

(4) Notification (a) Notification to Neighbor Base Station

For example, the base station 100 (control unit 153) notifies the basestation 300 of the operation of the base station 100 regardingtransmission of the signal over the directional beam.

More specifically, for example, the base station 100 (control unit 153)generates a message (a message for the base station 300) includingoperation information indicating the operation (e.g., suspension,restriction or continuation) of the base station 100 regardingtransmission of the signal over the directional beam. Thereafter, thebase station 100 transmits the message to the base station 300 throughan interface (e.g., an X2 interface) between the base station 100 andthe base station 300.

Accordingly, the base station 300 can recognize how interference of adirectional beam in the terminal apparatus 200 connected to the basestation 300 changes, for example.

(b) Notification to Terminal Apparatus

The base station 100 (control unit 153) may notify the base station 300of the operation of the base station 100 regarding transmission of thesignal over the directional beam.

The base station 100 (control unit 153) may decide and execute, as theoperation, change of a configuration of a reference signal for channelquality measurement transmitted over the directional beam (includinglengthening the period). In this case, the base station 100 may notifythe terminal apparatus 200 of the change of the configuration.

(5) Cancellation of Operation

For example, the base station 100 (control unit 153) cancels theoperation of the base station 100 regarding transmission of the signalover the directional beam when a cancellation condition is satisfied.For example, the operation is suspension, restriction, or the like oftransmission of the signal over the directional beam. Accordingly, it ispossible to set suspension of or restriction on transmission of thesignal over the directional beam within a limited range, for example.

(a) Elapsed Time

For example, the cancellation condition includes a condition that anelapsed time from initiation of the operation exceed a predeterminedtime. That is, the base station 100 (control unit 153) cancels theoperation when the elapsed time from initiation of the operation exceedsthe predetermined time.

More specifically, the base station 100 (control unit 153) starts atimer when the operation of the base station 100 regarding transmissionof the signal over the directional beam is initiated, for example.Thereafter, the base station 100 (control unit 153) cancels theoperation when the timer expires.

Accordingly, it is possible to set suspension of or restriction ontransmission of the signal over the directional beam within a limitedtime, for example.

(b) Reception of Cancellation Information

For example, the cancellation condition includes reception, by the basestation 100, of cancellation information about cancellation of theoperation from the base station 300. That is, the base station 100(control unit 153) cancels the operation upon receiving the cancellationinformation from the base station 300.

For example, the base station 300 generates a cancellation messageincluding the cancellation information and transmits the cancellationmessage to the base station 100.

(b-1) Cancellation Information

Beam Information

For example, the cancellation information includes information forspecifying the directional beam (i.e., specification information).

Restriction Information

The cancellation information may include restriction informationindicating restriction on transmission of the signal over thedirectional beam after cancellation.

Specifically, the restriction information may indicate, as therestriction, radio resources or a period in which the signal istransmitted over the directional beam. Also, the restriction informationmay indicate a configuration of a reference signal for channel qualitymeasurement transmitted over the directional beam as the restriction.

In such a case, the base station 100 may transmit the signal over thedirectional beam in accordance with the restriction indicated by therestriction information after cancellation of the operation.

According to such restriction information, it is possible to adjust abalance between transmission of a directional beam and avoidance orsuppression of interference more flexibly, for example.

(b-2) Trigger of Transmission of Cancellation Information

For example, the base station 300 transmits the cancellation informationto the base station 100 when interference of the directional beam isassumed to be small.

First Example

As a first example, the base station 300 transmits the cancellationinformation to the base station 100 when the terminal apparatus 200(terminal apparatus 200 connected to the base station 300) whichreceives interference of the directional beam finishes receiving a datasignal.

Second Example

As a second example, the base station 300 transmits the cancellationinformation to the base station 100 when the terminal apparatus 200(terminal apparatus 200 connected to the base station 300) whichreceives interference of the directional beam at a certain positionmoves from the certain position to a different position.

Third Example

As a third example, the terminal apparatus 200 connected to the basestation 300 may detect a radio resource having a small amount ofinterference from among radio resources in which reference signals forchannel quality measurement are transmitted. In this case, the basestation 300 may transmit cancellation information related to suspensionof or restriction on a reference signal for channel quality measurementto the base station 100. The cancellation information may includeinformation indicating a configuration including the radio resource asrestriction information indicating restriction on transmission of areference signal for channel quality measurement over the directionalbeam after cancellation. Thereafter, the base station 100 may transmit areference signal for channel quality measurement having theconfiguration over the directional beam.

Note that the terminal apparatus 200 (interference amount calculationunit 241) may calculate an amount of interference from a referencesignal for channel quality measurement transmitted by a neighbor basestation (including a neighbor base station other than the base station100) of the base station 300 that is a serving base station. Thereafter,the terminal apparatus 200 (detection unit 243) may detect a radioresource having a small amount of interference (e.g., a radio resourcehaving an amount of interference less than a threshold value) from amongradio resources in which the reference signal is transmitted. Then, theterminal apparatus 200 (reporting unit 245) may report the radioresource having a small amount of interference to the base station 300.Thereafter, the base station 300 may transmit cancellation informationto the base station 100, and the cancellation information may includeinformation indicating a configuration including the radio resource asrestriction information.

A trigger of transmission of the cancellation information to the basestation 100 is not limited to the aforementioned first to third examplesand may be a different one.

(c) Notification of Completion of Cancellation

For example, the base station 100 (control unit 153) notifies the basestation of completion of cancellation of the operation. For example, thebase station 100 (control unit 153) transmits a message includingcancellation completion information indicating completion ofcancellation of the operation to the base station 300.

Note that the base station 100 (control unit 153) may notify theterminal apparatus 200 of completion of cancellation of the operation.

5. PROCESSING FLOW

Next, an example of a process according to the embodiment of the presentdisclosure will be described with reference to FIGS. 11 to 13.

(1) First Example

FIG. 11 is a sequence diagram illustrating a first example of aschematic flow of the process according to the embodiment of the presentdisclosure.

The base station 100 transmits a reference signal for channel qualitymeasurement (e.g., a CSI-RS) (S401).

The terminal apparatus 200 connected to the base station 300 calculatesan amount of interference from the reference signal (S403). For example,the terminal apparatus 200 calculates an amount of interference of eachof a plurality of directional beams which can be formed by the basestation 100.

Further, the terminal apparatus 200 reports the amount of interferenceto the base station 300 (S405). For example, the terminal apparatus 200transmits an interference report indicating the amount of interferenceto the base station 300.

The base station 300 provides, to the base station 100, information(i.e., interference beam information) about a directional beam which isan interference source for the terminal apparatus 200 connected to thebase station 300 (e.g., a directional beam having a large amount ofinterference in the terminal apparatus 200) from among the plurality ofdirectional beams (S407). For example, the base station 300 transmits amessage including the interference beam information to the base station100.

The base station 100 acquires the interference beam information anddecides an operation of the base station 100 regarding transmission of asignal over the directional beam on the basis of the interference beaminformation (S409). Then, the base station 100 executes the operation(S411). Also, the base station 100 notifies the base station 300 of theoperation (S413). For example, the base station 100 transmits a messageincluding operation information indicating the operation to the basestation 300.

Note that the base station 100 may notify the terminal apparatus 200connected to the base station 100 of the operation. Also, the basestation 300 may notify the terminal apparatus 200 connected to the basestation 300 of the operation.

(2) Second Example

FIG. 12 is a sequence diagram illustrating a second example of aschematic flow of the process according to the embodiment of the presentdisclosure.

Here, description of steps S431 to S441 and S445 in the second exampleillustrated in FIG. 12 is the same as description of steps S401 to S413in the first example illustrated in FIG. 11, and thus only steps S443and S447 to S451 will be described.

The base station 100 starts a timer when an operation regardingtransmission of a signal over a directional beam (i.e., the operationdecided in step S431) is initiated (S443).

Thereafter, the base station 100 cancels the operation (S449) when thetimer expires (S447). Then, the base station 100 notifies the basestation 300 of completion of cancellation of the operation (S451). Forexample, the base station 100 transmits a message including cancellationcompletion information indicating completion of cancellation of theoperation to the base station 300.

Note that the base station 100 may notify the terminal apparatus 200connected to the base station 100 of completion of cancellation of theoperation. Also, the base station 300 may notify the terminal apparatus200 connected to the base station 300 of completion of cancellation ofthe operation.

(3) Third Example

FIG. 13 is a sequence diagram illustrating a third example of aschematic flow of the process according to the embodiment of the presentdisclosure.

Here, description of steps S461 to S473 in the third example illustratedin FIG. 13 is the same as description of steps S401 to S413 in the firstexample illustrated in FIG. 11, and thus only steps S475 to S479 will bedescribed.

The base station 300 transmits cancellation information aboutcancellation of an operation regarding transmission of a signal over adirectional beam (i.e., the operation decided in step S469) to the basestation 100 (S475). For example, the base station 300 transmits amessage including the cancellation information to the base station 100.

The base station 100 cancels the operation in response to reception ofthe cancellation information (S477). Then, the base station 100 notifiesthe base station 300 of completion of cancellation of the operation(S479). For example, the base station 100 transmits a message includingcancellation completion information indicating completion ofcancellation of the operation to the base station 300.

Note that the base station 100 may notify the terminal apparatus 200connected to the base station 100 of completion of cancellation of theoperation. Also, the base station 300 may notify the terminal apparatus200 connected to the base station 300 of completion of cancellation ofthe operation.

6. APPLICATION EXAMPLES

The technique according to the present disclosure is applicable tovarious products. The base station 100 may also be implemented, forexample, as any type of evolved Node B (eNB) such as macro eNBs andsmall eNBs. Small eNBs may cover smaller cells than the macrocells ofpico eNBs, micro eNBs, or home (femt) eNBs. Instead, the base station100 may be implemented as another type of base station such as Nodes Bor base transceiver stations (BTSs). The base station 100 may includethe main apparatus (which is also referred to as base station apparatus)that controls wireless communication and one or more remote radio heads(RRHs) that are disposed at different locations from that of the mainapparatus. Also, various types of terminals described below may functionas the base station 100 by temporarily or semi-permanently executing thefunctionality of the base station. Furthermore, at least some ofcomponents of the base station 100 may be realized in a base stationapparatus or a module for a base station apparatus.

Further, the terminal apparatus 200 may be implemented as a mobileterminal such as smartphones, tablet personal computers (PCs), notebookPCs, portable game terminals, portable/dongle mobile routers, anddigital cameras, or an in-vehicle terminal such as car navigationapparatuses. The terminal apparatus 200 may be implemented as a machinetype communication (MTC) for establishing a machine to machinecommunication (M2M). Furthermore, at least some of components of theterminal apparatus 200 may be implemented as a module (e.g. integratedcircuit module constituted with a single die) that is mounted on theseterminals.

6.1. Application Examples for Base Station First Application Example

FIG. 14 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 and the base stationapparatus 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or a plurality of antennaelements (e.g. a plurality of antenna elements constituting a MIMOantenna) and is used for the base station apparatus 820 to transmit andreceive a wireless signal. The eNB 800 may include the plurality of theantennas 810 as illustrated in FIG. 14, and the plurality of antennas810 may, for example, correspond to a plurality of frequency bands usedby the eNB 800. It should be noted that while FIG. 14 illustrates anexample in which the eNB 800 includes the plurality of antennas 810, theeNB 800 may include the single antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a wireless communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of an upper layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data in asignal processed by the wireless communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may generate a bundled packet by bundling data from aplurality of base band processors to transfer the generated bundledpacket. The controller 821 may also have a logical function ofperforming control such as radio resource control, radio bearer control,mobility management, admission control, and scheduling. The control maybe performed in cooperation with a surrounding eNB or a core network.The memory 822 includes a RAM and a ROM, and stores a program executedby the controller 821 and a variety of control data (such as, forexample, terminal list, transmission power data, and scheduling data).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to the core network 824. The controller821 may communicate with a core network node or another eNB via thenetwork interface 823. In this case, the eNB 800 may be connected to acore network node or another eNB through a logical interface (e.g. S1interface or X2 interface). The network interface 823 may be a wiredcommunication interface or a wireless communication interface forwireless backhaul. When the network interface 823 is a wirelesscommunication interface, the network interface 823 may use a higherfrequency band for wireless communication than a frequency band used bythe wireless communication interface 825.

The wireless communication interface 825 supports a cellularcommunication system such as long term evolution (LTE) or LTE-Advanced,and provides wireless connection to a terminal located within the cellof the eNB 800 via the antenna 810. The wireless communication interface825 may typically include a base band (BB) processor 826 and an RFcircuit 827. The BB processor 826 may, for example, performencoding/decoding, modulation/demodulation, multiplexing/demultiplexing,and the like, and performs a variety of signal processing on each layer(e.g. L1, medium access control (MAC), radio link control (RLC), andpacket data convergence protocol (PDCP)). The BB processor 826 may havepart or all of the logical functions as described above instead of thecontroller 821. The BB processor 826 may be a module including a memoryhaving a communication control program stored therein, a processor toexecute the program, and a related circuit, and the function of the BBprocessor 826 may be changeable by updating the program. The module maybe a card or blade to be inserted into a slot of the base stationapparatus 820, or a chip mounted on the card or the blade. Meanwhile,the RF circuit 827 may include a mixer, a filter, an amplifier, and thelike, and transmits and receives a wireless signal via the antenna 810.

The wireless communication interface 825 may include a plurality of theBB processors 826 as illustrated in FIG. 14, and the plurality of BBprocessors 826 may, for example, correspond to a plurality of frequencybands used by the eNB 800. The wireless communication interface 825 mayalso include a plurality of the RF circuits 827, as illustrated in FIG.14, and the plurality of RF circuits 827 may, for example, correspond toa plurality of antenna elements. FIG. 14 illustrates an example in whichthe wireless communication interface 825 includes the plurality of BBprocessors 826 and the plurality of RF circuits 827, but the wirelesscommunication interface 825 may include the single BB processor 826 orthe single RF circuit 827.

In the eNB 800 illustrated in FIG. 14, the information acquisition unit151 and the control unit 153 described above with reference to FIG. 8may be mounted in the wireless communication interface 825.Alternatively, at least some of the components may be mounted in thecontroller 821. As an example, the eNB 800 may be equipped with a moduleincluding some or all components of the wireless communication interface825 (for example, the BB processor 826) and/or the controller 821, andthe information acquisition unit 151 and the control unit 153 may bemounted in the module. In this case, the module may store a programcausing the processor to function as the information acquisition unit151 and the control unit 153 (that is, a program causing the processorto perform the operation of the information acquisition unit 151 and thecontrol unit 153) and execute the program. As another example, theprogram causing the processor to function as the information acquisitionunit 151 and the control unit 153 may be installed in the eNB 800, andthe wireless communication interface 825 (for example, the BB processor826) and/or the controller 821 may execute the program. As describedabove, the eNB 800, the base station apparatus 820, or the module may beprovided as an apparatus including the information acquisition unit 151and the control unit 153, and the program causing the processor tofunction as the information acquisition unit 151 and the control unit153 may be provided. A readable recording medium in which the program isrecorded may be provided.

In addition, in the eNB 800 shown in FIG. 14, the wireless communicationunit 120 described with reference to FIG. 8 may be implemented by thewireless communication interface 825 (for example, the RF circuit 827).Moreover, the antenna unit 110 may be implemented by the antenna 810. Inaddition, the network communication unit 130 may be implemented by thecontroller 821 and/or the network interface 823.

Second Application Example

FIG. 15 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 830 includes one or more antennas 840,a base station apparatus 850, and an RRH 860. Each of the antennas 840and the RRH 860 may be connected to each other via an RF cable. The basestation apparatus 850 and the RRH 860 may be connected to each other bya high speed line such as optical fiber cables.

Each of the antennas 840 includes a single or a plurality of antennaelements (e.g. antenna elements constituting a MIMO antenna), and isused for the RRH 860 to transmit and receive a wireless signal. The eNB830 may include a plurality of the antennas 840 as illustrated in FIG.15, and the plurality of antennas 840 may, for example, correspond to aplurality of frequency bands used by the eNB 830. FIG. 15 illustrates anexample in which the eNB 830 includes the plurality of antennas 840, butthe eNB 830 may include the single antenna 840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a wireless communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 14.

The wireless communication interface 855 supports a cellularcommunication system such as LTE and LTE-Advanced, and provides wirelessconnection to a terminal located in a sector corresponding to the RRH860 via the RRH 860 and the antenna 840. The wireless communicationinterface 855 may typically include a BB processor 856. The BB processor856 is the same as the BB processor 826 described with reference to FIG.14 except that the BB processor 856 is connected to an RF circuit 864 ofthe RRH 860 via the connection interface 857. The wireless communicationinterface 855 may include a plurality of the BB processors 856, asillustrated in FIG. 15, and the plurality of BB processors 856 may, forexample, correspond to a plurality of frequency bands used by the eNB830 respectively. FIG. 15 illustrates an example in which the wirelesscommunication interface 855 includes the plurality of BB processors 856,but the wireless communication interface 855 may include the single BBprocessor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (wireless communication interface 855) to the RRH860. The connection interface 857 may be a communication module forcommunication on the high speed line which connects the base stationapparatus 850 (wireless communication interface 855) to the RRH 860.

Further, the RRH 860 includes a connection interface 861 and a wirelesscommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(wireless communication interface 863) to the base station apparatus850. The connection interface 861 may be a communication module forcommunication on the high speed line.

The wireless communication interface 863 transmits and receives awireless signal via the antenna 840. The wireless communicationinterface 863 may typically include the RF circuit 864. The RF circuit864 may include a mixer, a filter, an amplifier and the like, andtransmits and receives a wireless signal via the antenna 840. Thewireless communication interface 863 may include a plurality of the RFcircuits 864 as illustrated in FIG. 15, and the plurality of RF circuits864 may, for example, correspond to a plurality of antenna elements.FIG. 15 illustrates an example in which the wireless communicationinterface 863 includes the plurality of RF circuits 864, but thewireless communication interface 863 may include the single RF circuit864.

In the eNB 830 illustrated in FIG. 15, the information acquisition unit151 and the control unit 153 described above with reference to FIG. 8may be mounted in the wireless communication interface 855 and thewireless communication interface 863. Alternatively, at least some ofthe components may be mounted in the controller 851. As an example, theeNB 830 may be equipped with a module including some or all componentsof the wireless communication interface 855 (for example, the BBprocessor 856) and/or the controller 851, and the informationacquisition unit 151 and the control unit 153 may be mounted in themodule. In this case, the module may store a program causing theprocessor to function as the information acquisition unit 151 and thecontrol unit 153 (that is, a program causing the processor to performthe operation of the information acquisition unit 151 and the controlunit 153) and execute the program. As another example, the programcausing the processor to function as the information acquisition unit151 and the control unit 153 may be installed in the eNB 830, and thewireless communication interface 855 (for example, the BB processor 856)and/or the controller 851 may execute the program. As described above,the eNB 830, the base station apparatus 850, or the module may beprovided as an apparatus including the information acquisition unit 151and the control unit 153, and the program causing the processor tofunction as the information acquisition unit 151 and the control unit153 may be provided. A readable recording medium in which the program isrecorded may be provided.

In addition, in the eNB 830 shown in FIG. 15, the wireless communicationunit 120 described with reference to FIG. 8 may be implemented by thewireless communication interface 863 (for example, the RF circuit 864).Moreover, the antenna unit 110 may be implemented by the antenna 840. Inaddition, the network communication unit 130 may be implemented by thecontroller 851 and/or the network interface 853.

6.2. Application Examples for Terminal Apparatus First ApplicationExample

FIG. 16 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology according tothe present disclosure may be applied. The smartphone 900 includes aprocessor 901, a memory 902, a storage 903, an external connectioninterface 904, a camera 906, a sensor 907, a microphone 908, an inputdevice 909, a display device 910, a speaker 911, a wirelesscommunication interface 912, one or more antenna switches 915, one ormore antennas 916, a bus 917, a battery 918, and a secondary controller919.

The processor 901 may be, for example, a CPU or a system on chip (SoC),and controls the functions of an application layer and other layers ofthe smartphone 900. The memory 902 includes a RAM and a ROM, and storesa program executed by the processor 901 and data. The storage 903 mayinclude a storage medium such as semiconductor memories and hard disks.The external connection interface 904 is an interface for connecting thesmartphone 900 to an externally attached device such as memory cards anduniversal serial bus (USB) devices.

The camera 906 includes an image sensor such as charge coupled devices(CCDs) and complementary metal oxide semiconductor (CMOS), and generatesa captured image. The sensor 907 may include a sensor group including,for example, a positioning sensor, a gyro sensor, a geomagnetic sensor,and an acceleration sensor. The microphone 908 converts a sound that isinput into the smartphone 900 to an audio signal. The input device 909includes, for example, a touch sensor which detects that a screen of thedisplay device 910 is touched, a key pad, a keyboard, a button, or aswitch, and accepts an operation or an information input from a user.The display device 910 includes a screen such as liquid crystal displays(LCDs) and organic light emitting diode (OLED) displays, and displays anoutput image of the smartphone 900. The speaker 911 converts the audiosignal that is output from the smartphone 900 to a sound.

The wireless communication interface 912 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 912 may typicallyinclude the BB processor 913, the RF circuit 914, and the like. The BBprocessor 913 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 914 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 916. The wireless communicationinterface 912 may be a one-chip module in which the BB processor 913 andthe RF circuit 914 are integrated. The wireless communication interface912 may include a plurality of BB processors 913 and a plurality of RFcircuits 914 as illustrated in FIG. 16. FIG. 16 illustrates an examplein which the wireless communication interface 912 includes a pluralityof BB processors 913 and a plurality of RF circuits 914, but thewireless communication interface 912 may include a single BB processor913 or a single RF circuit 914.

Further, the wireless communication interface 912 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelesslocal area network (LAN) system in addition to the cellularcommunication system, and in this case, the wireless communicationinterface 912 may include the BB processor 913 and the RF circuit 914for each wireless communication system.

Each antenna switch 915 switches a connection destination of the antenna916 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 912.

Each of the antennas 916 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 912. The smartphone 900 may include aplurality of antennas 916 as illustrated in FIG. 16. FIG. 16 illustratesan example in which the smartphone 900 includes a plurality of antennas916, but the smartphone 900 may include a single antenna 916.

Further, the smartphone 900 may include the antenna 916 for eachwireless communication system. In this case, the antenna switch 915 maybe omitted from a configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 912, and the secondarycontroller 919 to each other. The battery 918 supplies electric power toeach block of the smartphone 900 illustrated in FIG. 16 via a feederline that is partially illustrated in the figure as a dashed line. Thesecondary controller 919, for example, operates a minimally necessaryfunction of the smartphone 900 in a sleep mode.

In the smartphone 900 illustrated in FIG. 16, the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245described above with reference to FIG. 9 may be mounted in the wirelesscommunication interface 912. Alternatively, at least some of thecomponents may be mounted in the processor 901 or the secondarycontroller 919. As an example, the smartphone 900 may be equipped with amodule including some or all components of the wireless communicationinterface 912 (for example, the BB processor 913), the processor 901,and/or the secondary controller 919, and the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245may be mounted in the module. In this case, the module may store aprogram causing the processor to function as the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245(that is, a program causing the processor to perform the operation ofthe interference amount calculation unit 241, the detection unit 243and/or reporting unit 245) and execute the program. As another example,the program causing the processor to function as the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245may be installed in the smartphone 900, and the wireless communicationinterface 912 (for example, the BB processor 913), the processor 901,and/or the secondary controller 919 may execute the program. Asdescribed above, the smartphone 900 or the module may be provided as anapparatus including the interference amount calculation unit 241, thedetection unit 243 and/or reporting unit 245, and the program causingthe processor to function as the interference amount calculation unit241, the detection unit 243 and/or reporting unit 245 may be provided. Areadable recording medium in which the program is recorded may beprovided.

In addition, in the smartphone 900 shown in FIG. 16, the wirelesscommunication unit 220 described with reference to FIG. 9 may beimplemented by the wireless communication interface 912 (for example,the RF circuit 914). Moreover, the antenna unit 210 may be implementedby the antenna 916.

Second Application Example

FIG. 17 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus 920 to which the technologyaccording to the present disclosure may be applied. The car navigationapparatus 920 includes a processor 921, a memory 922, a globalpositioning system (GPS) module 924, a sensor 925, a data interface 926,a content player 927, a storage medium interface 928, an input device929, a display device 930, a speaker 931, a wireless communicationinterface 933, one or more antenna switches 936, one or more antennas937, and a battery 938.

The processor 921 may be, for example, a CPU or an SoC, and controls thenavigation function and the other functions of the car navigationapparatus 920. The memory 922 includes a RAM and a ROM, and stores aprogram executed by the processor 921 and data.

The GPS module 924 uses a GPS signal received from a GPS satellite tomeasure the position (e.g. latitude, longitude, and altitude) of the carnavigation apparatus 920. The sensor 925 may include a sensor groupincluding, for example, a gyro sensor, a geomagnetic sensor, and abarometric sensor. The data interface 926 is, for example, connected toan in-vehicle network 941 via a terminal that is not illustrated, andacquires data such as vehicle speed data generated on the vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g. CD or DVD) inserted into the storage medium interface 928. Theinput device 929 includes, for example, a touch sensor which detectsthat a screen of the display device 930 is touched, a button, or aswitch, and accepts operation or information input from a user. Thedisplay device 930 includes a screen such as LCDs and OLED displays, anddisplays an image of the navigation function or the reproduced content.The speaker 931 outputs a sound of the navigation function or thereproduced content.

The wireless communication interface 933 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 933 may typicallyinclude the BB processor 934, the RF circuit 935, and the like. The BBprocessor 934 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 935 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 937. The wireless communicationinterface 933 may be a one-chip module in which the BB processor 934 andthe RF circuit 935 are integrated. The wireless communication interface933 may include a plurality of BB processors 934 and a plurality of RFcircuits 935 as illustrated in FIG. 17. FIG. 17 illustrates an examplein which the wireless communication interface 933 includes a pluralityof BB processors 934 and a plurality of RF circuits 935, but thewireless communication interface 933 may be a single BB processor 934 ora single RF circuit 935.

Further, the wireless communication interface 933 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelessLAN system in addition to the cellular communication system, and in thiscase, the wireless communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each wireless communicationsystem.

Each antenna switch 936 switches a connection destination of the antenna937 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 933.

Each of the antennas 937 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 933. The car navigation apparatus 920includes a plurality of antennas 937 as illustrated in FIG. 17. FIG. 17illustrates an example in which the car navigation apparatus 920includes a plurality of antennas 937, but the car navigation apparatus920 may include a single antenna 937.

Further, the smartphone 920 may include the antenna 937 for eachwireless communication system. In this case, the antenna switch 936 maybe omitted from a configuration of the car navigation apparatus 920.

The battery 950 supplies electric power to each block of the carnavigation apparatus 930 illustrated in FIG. 17 via a feeder line thatis partially illustrated in the figure as a dashed line. The battery 950accumulates the electric power supplied from the vehicle.

In the car navigation apparatus 920 illustrated in FIG. 17, theinterference amount calculation unit 241, the detection unit 243 and/orreporting unit 245 described above with reference to FIG. 9 may bemounted in the wireless communication interface 933. Alternatively, atleast some of the components may be mounted in the processor 921. As anexample, the car navigation apparatus 920 may be equipped with a moduleincluding some or all components of the wireless communication interface933 (for example, the BB processor 934), and the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245may be mounted in the module. In this case, the module may store aprogram causing the processor to function as the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245(that is, a program causing the processor to perform the operation ofthe interference amount calculation unit 241, the detection unit 243and/or reporting unit 245) and execute the program. As another example,the program causing the processor to function as the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245may be installed in the car navigation apparatus 920, and the wirelesscommunication interface 933 (for example, the BB processor 934) and/orthe processor 921 may execute the program. As described above, the carnavigation apparatus 920 or the module may be provided as an apparatusincluding the interference amount calculation unit 241, the detectionunit 243 and/or reporting unit 245, and the program causing theprocessor to function as the interference amount calculation unit 241,the detection unit 243 and/or reporting unit 245 may be provided. Areadable recording medium in which the program is recorded may beprovided.

In addition, in the car navigation apparatus 920 shown in FIG. 17, thewireless communication unit 220 described with reference to FIG. 9 maybe implemented by the wireless communication interface 933 (for example,the RF circuit 935). Moreover, the antenna unit 210 may be implementedby the antenna 937.

The technology of the present disclosure may also be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of thecar navigation apparatus 920, the in-vehicle network 941, and a vehiclemodule 942. In other words, the in-vehicle system (or a vehicle) 940 maybe provided as a device which includes the interference amountcalculation unit 241, the detection unit 243 and/or reporting unit 245.The vehicle side module 942 generates vehicle data such as vehiclespeed, engine speed, and trouble information, and outputs the generateddata to the in-vehicle network 941.

7. CONCLUSION

Each apparatus and each process according to the embodiment of thepresent disclosure have been described above with reference to FIGS. 5to 17.

According to the embodiment of the present disclosure, the base station100 includes the information acquisition unit 151 that acquiresinformation about a directional beam which is an interference source forthe terminal apparatus 200 connected to the base station 300 (a neighborbase station of the base station 100), from among a plurality ofdirectional beams which can be formed by the base station 100, theinformation being provided by the base station 300, and the control unit153 that decides an operation of the base station 100 regardingtransmission of a signal over the directional beam on the basis of theinformation.

Accordingly, it is possible to further decrease interference of adirectional beam between cells, for example.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Although an example is described in which the system is a system that iscompliant with LTE, LTE-Advanced, or a communication scheme thatconforms to them, the present disclosure is not limited to such anexample. For example, the communication system may be a system thatconforms to another communication standard.

Further, it is not always necessary to execute the processing steps inthe processing in the present specification in chronological order inorder described in the flowcharts or the sequence diagrams. For example,the processing steps in the above-described processing may be executedin order different from the order described in the flowcharts or thesequence diagrams or may be executed in parallel.

In addition, a computer program for causing a processor (for example, aCPU, a DSP, or the like) provided in a device of the presentspecification (for example, a base station, a base station apparatus ora module for a base station apparatus, or a terminal apparatus or amodule for a terminal apparatus) to function as a constituent element ofthe device (for example, the information acquisition unit, the controlunit, or the like) (in other words, a computer program for causing theprocessor to execute operations of the constituent element of thedevice) can also be created. In addition, a recording medium in whichthe computer program is recorded may also be provided. Further, a devicethat includes a memory in which the computer program is stored and oneor more processors that can execute the computer program (a basestation, a base station apparatus or a module for a base stationapparatus, or a terminal apparatus or a module for a terminal apparatus)may also be provided. In addition, a method including an operation ofthe constituent element of the device (for example, the informationacquisition unit, the communication control unit, or the like) is alsoincluded in the technology of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art based on the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

An apparatus including:

an acquisition unit that acquires information about a directional beamthat is provided from a neighbor base station of a base station, thedirectional beam serving as an interference source for a terminalapparatus connected to the neighbor base station among a plurality ofdirectional beams which is able to be formed by the base station; and

a control unit that decides an operation of the base station regardingtransmission of a signal over the directional beam on the basis of theinformation.

(2)

The apparatus according to (1),

in which the signal includes a data signal.

(3)

The apparatus according to (1) or (2),

in which the signal includes a reference signal for channel qualitymeasurement.

(4)

The apparatus according to (3),

in which the reference signal for channel quality measurement is achannel state information reference signal (CSI-RS).

(5)

The apparatus according to any one of (1) to (4),

in which the control unit decides suspension of transmission of thesignal over the directional beam as the operation.

(6)

The apparatus according to any one of (1) to (5),

in which the control unit decides restriction on transmission of thesignal over the directional beam as the operation.

(7)

The apparatus according to (6),

in which the restriction includes restriction on a radio resource inwhich a data signal is transmitted over the directional beam.

(8)

The apparatus according to (7),

in which the restriction includes restriction on a time resource inwhich a data signal is transmitted over the directional beam.

(9)

The apparatus according to any one of (6) to (8),

in which the restriction includes lengthening a period of transmissionof a reference signal for channel quality measurement over thedirectional beam.

(10)

The apparatus according to any one of (1) to (9),

in which the control unit notifies the neighbor base station of theoperation of the base station.

(11)

The apparatus according to any one of (1) to (10),

in which the control unit notifies a terminal apparatus of the operationof the base station.

(12)

The apparatus according to any one of (1) to (11),

in which the information about the directional beam includes informationfor specifying the directional beam.

(13) The apparatus according to any one of (1) to (12),

in which the control unit cancels the operation of the base station inthe case where a cancellation condition is satisfied.

(14)

The apparatus according to (13),

in which the cancellation condition includes a condition that an elapsedtime from initiation of the operation exceeds a predetermined time.

(15)

The apparatus according to (13) or (14),

in which the cancellation condition includes reception, by the basestation, of cancellation information about cancellation of the operationfrom the neighbor base station.

(16)

The apparatus according to (15),

in which the cancellation information includes restriction informationindicating restriction on transmission of the signal over thedirectional beam after cancellation.

(17)

The apparatus according to (16),

in which the restriction information indicates, as the restriction, aradio resource or a period in which the signal is transmitted over thedirectional beam, or a configuration of a reference signal for channelquality measurement transmitted over the directional beam.

(18)

The apparatus according to any one of (1) to (17),

in which the apparatus is the base station, a base station apparatus forthe base station, or a module for the base station apparatus.

(19)

A method including, by a processor:

acquiring information about a directional beam that is provided from aneighbor base station of a base station, the directional beam serving asan interference source for a terminal apparatus connected to theneighbor base station among a plurality of directional beams which isable to be formed by the base station; and

deciding an operation of the base station regarding transmission of asignal over the directional beam on the basis of the information.

(20)

An apparatus including:

a calculation unit that calculates an amount of interference from areference signal for channel quality measurement transmitted by aneighbor base station of a serving base station;

a detection unit that detects a radio resource having a small amount ofinterference from among radio resources to which the reference signal istransmitted; and

a reporting unit that reports the radio resource having a small amountof interference to a base station.

(21)

A program causing a processor to execute:

acquiring information about a directional beam that is provided from aneighbor base station of a base station, the directional beam serving asan interference source for a terminal apparatus connected to theneighbor base station among a plurality of directional beams which isable to be formed by the base station; and

deciding an operation of the base station regarding transmission of asignal over the directional beam on the basis of the information.

(22)

A readable recording medium having a program stored therein, the programcausing a processor to execute:

acquiring information about a directional beam that is provided from aneighbor base station of a base station, the directional beam serving asan interference source for a terminal apparatus connected to theneighbor base station among a plurality of directional beams which isable to be formed by the base station; and

deciding an operation of the base station regarding transmission of asignal over the directional beam on the basis of the information.

(23)

A method including, by a processor:

calculating an amount of interference from a reference signal forchannel quality measurement transmitted by a neighbor base station of aserving base station;

detecting a radio resource having a small amount of interference fromamong radio resources to which the reference signal is transmitted; and

reporting the radio resource having a small amount of interference to abase station.

(24)

A program causing a processor to execute:

calculating an amount of interference from a reference signal forchannel quality measurement transmitted by a neighbor base station of aserving base station;

detecting a radio resource having a small amount of interference fromamong radio resources to which the reference signal is transmitted; and

reporting the radio resource having a small amount of interference to abase station.

(25)

A readable recording medium having a program stored therein, the programcausing a processor to execute:

calculating an amount of interference from a reference signal forchannel quality measurement transmitted by a neighbor base station of aserving base station;

detecting a radio resource having a small amount of interference fromamong radio resources to which the reference signal is transmitted; and

reporting the radio resource having a small amount of interference to abase station.

REFERENCE SIGNS LIST

-   1 system-   100 base station-   101 cell-   151 information acquisition unit-   153 control unit-   200 terminal apparatus-   241 interference calculation unit-   243 detection unit-   245 reporting unit-   300 base station-   301 cell

1. A communication apparatus comprising: circuitry configured to limitresources used for transmission of reference signalling based on firstinformation; receive information related to channel quality measurementfrom a terminal device; and notify an operation of the communicationapparatus to another communication apparatus.
 2. The communicationapparatus of claim 1, wherein the reference signaling is used forchannel quality measurement or interference situation detection.
 3. Thecommunication apparatus of claim 15, wherein the reference signalling achannel state information reference signal (CSI-RS) used for channelquality measurement.
 4. The communication apparatus of claim 3, whereinthe circuitry is configured to change a configuration of the referencesignaling.
 5. The communication apparatus of claim 4, wherein theconfiguration is related to at least one of resources used fortransmission the reference signal and/or a reference signal sequence. 6.The communication apparatus of claim 5, wherein the resources used fortransmitting the reference signalling includes radio resources and/ortime resources.
 7. The communication apparatus of claim 6, wherein theconfiguration is related to lengthening a period of transmission of thereference signalling.
 8. The communication apparatus of claim 1, whereinthe another communication apparatus is a peripheral base station or aterminal apparatus.
 9. The communication apparatus of claim 1, whereinthe circuitry is configured to release the limitation on the resourcesused for transmission of the reference signalling when a predeterminedcondition is satisfied.
 10. The communication apparatus of claim 9,wherein the predetermined condition is a time elapsed from initiation oflimiting the resources used for transmission of the reference signallingexceeds a predetermined period of time.
 11. The communication apparatusof claim 9, wherein the communication apparatus is a base station, andthe circuitry is configured to release the limitation on the resourcesuses for transmission of the reference signaling upon receivinginformation about cancellation of limiting the resources from a neighborbase station.
 12. The communication apparatus according to claim 11,wherein the information about cancellation of limiting the resourcesindicates restriction information indicating transmission restriction ofthe reference signal transmitted by a directional beam.
 13. A methodperformed by a base station, the method comprising: limiting, byprocessing circuitry of the base station, resources used fortransmission of reference signalling based on first information;receiving, by a communication interface of the base station, informationrelated to channel quality measurement from a terminal device; andnotifying, by the communication interface of the base station, anoperation of the communication apparatus to at least one of another basestation and a terminal device.
 14. A non-transitory computer-readablemedium including computer-program instructions, which when executed by abase station, cause the base station to: limit resources used fortransmission of reference signalling based on first information; receiveinformation related to channel quality measurement from a terminaldevice; and notify an operation of the communication apparatus to atleast one of another base station and a terminal device.